Automatic resetting device for governors



Jama H7, 195@ N. R. RICHMOND AUTOMATIC RESETTING DEVICE FOR GOVERNORSOriginal Filed Oct. 2, 1940 III ifa

INVENTOR Zm and f 550mg ATTORNEY Il@ www' 9 Patented Jan. 17, 1950AUTOMATIC RESETIING DEVICE FOR GOVERNORS Nelson R. Richmond,Thompsonville, Conn., as-

sgnor to United AircraftV- Corporation, East Hartford, Conn., acorporation of Delaware Original application October 2, 1940, Serial No.359,370. Divided and this application January 2.6, 194,4, Serial No.,519,799

7 Claims. 1 i

This :application is. adivsion ofl U. S. application .serial1 No.359,370, filed October 2, 1940 (Patent No. 2,352,736, dated July 4,1944).

This-invention-,relatesto improvements in govemilie devices .and hasparticular reference to an improved governor .control for acontrollablepitch propeller.`

An `object ofY the invention resides in the provision. of animproved.governor control of the character indicatedhaving a manually actuatablesetting deviceand an. automatic setting device 'for ii-isettngt thegovernor for operating condi- 'tionsunder which the manual settingdevice does not.providel adequate. control and for returning the.governor tothe manual setting when such special operating conditionsterminate.

vAsome.what.more specific object resides in thev pnoyi'sionr a` governorfor a controllable-pitch propellerotmeans for automatically resettingthe governor for propeller speeds below a predetermined toprevent thepropeller from attainingv a, speed materially above thev speed for whichthe governor` is normally set as the speed of the. propeller is,increased. Y

Other objects and advantages will be more particularly .pointed outhereinafter or will become, apparent as the description proceeds.

In. the accompanying. drawing, in which like reierencenumerals are usedto designatesimilar parts` throughout,` there is illustrated a suitablemechanical embodiment for thepurpose of disclosing the invention. Thedrawing, however, is for. the purpose of: illustration .only and is notto betaken as limiting-or restricting the invention since it will vbeapparent to those skilled in the thatv various changesAv in` theillustrated construction may .be .resorted to without in any wayexceeding the scope of the invention.

In the drawing, Fig. 1 is a longitudinalv sectional. view through. agovernor-constructed according tothe invention.

'E is aschematic sectional view. showing the grernor applied tocontrolthe pitch of a con- Reliable-pitch; propeller, and

Fig- 3 is a schematic view of the pitch changy.

ing mechanism.

Referring to the drawing in detail, the numeral Iligenerally. indicatestheI speed governor and the numeral 1.2 generally indicates acontrollablepitch propeller @the pitch of which` is regu-latedbythe-action ofl the governor |10. In the illustrated arrangement .the4governor actuates a valve for controlling the pitch ofA :ahydro-controllable.

ieaiherng-typepropeller .onezillustrative form of which is .clearlyillustrated and describedgin fili (Cl. Utl-160.19)

2 Unitedv States Patent No. 2,174,717, issued October 3, 1939, to FrankW. Caldwell et al., for Multiposition controllable pitch propeller.

Itis well known to operate a controllable-pitch propeller under governorcontrol to establish a substantially constant engine speed by changingthe propeller pitch to vary the load on the engine whenever the enginetends to speed up or slow down. It is also wellA known to manuallyadjust the governor setting so that the propeller will maintain theengine speed substantially constant at a selected rate.

In the hydro-controllable propeller and con'- trol lsystem illustratedVin Fig. 2, `hydraulic fluid, such as engine lubricating oil atlubricating oil pressure, is supplied through the channel I4 to theintake of a booster pump IIS. The outlet of the pump is connected with apressure chamber I8 one end of which leads into a valve bore '-20 andthe other end of which leads to a pressure relief valve 22 which isoperative to maintain a predeterminedpuid pressure in the chamber I8 orto maintain the fluid pressure in the chamber I8` a predetermined amountabove the fluid pressure required to operate the propeller. A valveplunger 24 is slidable in the bore 2l)v and controls the ports 26 and 28 in such a manner that` the propeller line 30y may be connected withthe pressure chamber I8 or may be vented to drain through the hollowplunger 24 and Athe lower end of the bore 20, At its upper end theplunger 24 is operatively connected to a speed governor havingcentrifugally actuated flyba'lls 32 opposed by a Speeder spring 34. Theupper end ofthe speeder spring rests against the lower end of a movableabutmentv 36 which is adjustable to various positions by the manuallyactuatable mechanismA including the pulley 38 and pinion 40 the teeth ofwhich mesh with rack teeth provided on one side lof the movableabutment. BY rotating the pulley .38 the lowermost operative position ofthe abutment 36' and the load on the Speeder spring 3,4 can be changedto change the speed setting of the governor. If desired the propeller I2may be of the feathering type and the unieathering operationsy may b econtrolled lby the high pressure pump 42 connected to the propeller line30 through the pressure operated cut-off valve 44 which actsl to cut-offthe connection 46 between the governor operated valve and the propellerwhenever the high pressure pump 42 is' operated and simultaneouslyconnect the outlet of the high pressurev pump directly with thepropeller line A30.

'The .governor setting mechanism may be adjusted for a selected enginespeed and will then maintain the engine at or near the selected speed byvarying the propeller pitch as long as the engine develops suiicientpower to rotate the propeller at the selected speed. If, however, theengine is brought to an idling condition for som'e particular maneuver,such as a dive or a landing glide, it will not develop suilicient powerto maintain the speed for which the governor is set. The governor willthen change the propeller pitch setting in an attempt to reduce theengine load suiiiciently to maintain the selected speed and willmaintain the propeller in this flat pitch condition as long as theengine power remains insuihcient to rotate the propeller at the selectedspeed. If, with the engine at reduced power and the propeller in itsflat pitch condition, the engine power is increased, the propeller pitchwill not be changed until the engine speed begins to exceed theV speedfor which the governor is set. As soon as the selected speed is reachedthe governor will immediately begin to function to increase thepropeller pitch and increase the load on the engine to maintain theselected speed. However, as an appreciable time interval is required forthe governor to change the propeller pitch from the flat or extreme lowpitch condition to a pitch angle sufficient to slow down the engine,during this interval the engine speed may go considerably beyond thespeed for which the governor is set and, if the engine power isincreased rapidly, this overshooting or overspeeding of the propellermay reach` dangerous proportions before the governor control canincrease the'propeller pitch a suilicient amount to slow down theengine. It is among the objects of the present invention to incorporateinto a propeller speed control device of the character indicatedsuitable means for preventing this overspeeding of the propellerincident to a rapid increase in engine power from a power value belowthat necessary to drive the propeller at the speed for which the speedcontrolling governor is set and one illustrative form of such a deviceis particularly shown in Fig. l.

The abutment 36 is formed in two parts, as indicated at 48 and 50. Ofthese the outer part 48 is in the form of a sleeve slidable in the boreof the cylinder 52 formed on the governor cap 54 immediately over theupper end of the spring 34. This sleeve has rack teeth 56 along one sidethereof meshing with the teeth of the adjusting pinion 40 and isprovided at its lower end with a stop in the form of an internal ilangeor inset 58. A piston 50 is slidable in the sleeve 48 and in the upperreduced portion of the bore of the cylinder 52 and carries in its lowerend an adjustable spring seat 62. With the propeller under the controlof the governor the lower end of piston rests against the internalilange 58. A fluid connection 64 leads from the propellerconnected oilchamber 46 to the space at the closed end of the cylinder 52 on top ofthe piston 60, so that oil at propeller oil pressure issupplied to thecylinder to urge the piston 60 downwardly relative to the sleeve 48against the stop 58.

When the plunger 24 is in position to connect the ports 23 and 2G theoil pressure in the chamber 46 will be the same as that in the pumpoutlet chamber' i3 and when the plunger 24 is in position to vent theport 26 through the hollow plunger 24 the pressure in the chamber 46will be the pressure exerted on the oil in the propeller line by thecentrifugal action of the pro peller blades tending to turn towardstheir low pitch position. It is only when the propeller blades areagainst the low pitch limit stops 59, 59 that no uid pressure will bepresentv in the chamber 46 and under these circumstances the piston 60may rise to relieve the load on the governor speeder spring 34.

Assuming that the engine power has been reduced so that the engine is nolonger able to rotate the propeller at the speed for which the governoris manually set and that, in its effort to relieve the engine load andmaintain the selected speed, the governor has maintained the plunger 24in a position to vent the propeller line through the port 26 until stops59, 59 operate to prevent further pitch reduction and no pressure isleft in the propeller line and the chamber 46, the piston 60 will thenrise in the cylinder 52 and leave the stop 5B at the Sametime relievingthe load on the Speeder spring 34 and setting the governor for a muchlower speed than that forE which it was set by the manual control. Forin stance we might assume that the manual adjustment is set for 2,000revolutionsper minute and when the piston 60 is at the closed end of thecylinder 52 the settingY is for 1,000 revolu tion per minute. If now theengine power is increased and the engine and propeller begin to speedup, the pump I6 will begin to force oil into` the outlet chamber I3 andas soon as the speed has reached 1,000 R. P. M. the governor will act.to connect the ports 28 and 26 to admit oilto the propeller pitchchanging mechanism through passages 46 and 30 to start increasing thepropeller pitch. As the oil pressure in the propeller line 30 builds up,this pressure will be transmitted through conduit 54 to the top of thepiston 60 and will begin to change the governor setting. We will thushave a condition in which the propeller pitch is being increased toretard the engine speed and the governor setting is being changed towarda higher speed setting at the same time. With properly proportionedparts and fluid connections thepiston will reach the stop 58 atsomewhere near the same time that the engine speed reaches the speed atwhich the governor is set. Since the propeller mechanism is full of oilat this time and the propeller pitch has already been increased to bringthe engine and propellerspeeds under control of the governor at thegradually increasing speed setting, when the en-V gine and propellerspeed reaches the speed for which the governor is set the governor willalready be in control of the propeller pitch and the speed will bequickly brought tol the ,speed for which the governor is set withsubstantially:

no overspeeding oi the propeller at this period. As long as the powerdeveloped by theengine is suiiicientto drive the propeller at the speedfor which the governor is set there will be suirlcient oil pressure ontop of the piston 60 to maintain the piston in contact with the stop 58and lthe speed setting of the governor will remain that at which thegovernor is set by the manual adjusting mechanism.

While a particular mechanical arrangement has been hereinabove describedand illustrated in the accompanying drawing for the purpose ofdisclosing the invention, it is to be understood that the invention isnot limited to the particular construction so illustrated and described,but that such changes in the size, shapev and arrangementv of thevarious' parts maybe resorted to as conci?.-

within the scope of the sub-joined claims.

encased Having now dscribeltlthe'v invention so that the samawhat it isdesiredftosecure by Letters P'atentisas follows:

1L In combination, a propeller having. pitch changing mechanism, a lowpitch stop, a governor having` a spring and a valve, and centrifugalweights balanced against Saidspring and connected'to move said valve forcontrolling the application of pressure fluidto Vand the draining ofiiuid fromY the pitch changing mechanism oiK said propeller, a two partabutmentforl the; spring, one part of which is manually adjustableduring operation of the propeller and acts as a stop for the other part,said other part serving as an abutmentl for said spring and beinghydraulically actuated and held against said abutment stop by thehydraulic pressure in said pitch changing mechanism, but movable by thegovernor spring to another position upon failure of the hydraulicpressure in said pitch changing mechanism due to movement of thepropeller against said low pitch stop.

2. In combination with a controllable pitch propeller having anhydraulically actuated pitch changing mechanism and means defining a lowpitch position, a source of hydraulic fluid under pressure for operatingsaid pitch changing mechanism, a speed responsive governor, governorspeed selecting means having a range of normal speed settings, and avalve operated by said governor for connecting said pitch changingmechanism with said source to change the propeller pitch in onedirection and for connecting said pitch changing mechanism with drain tochange the propeller pitch in the other direction,hydraulically-actuated mechanism responsive to the hydraulic pressure insaid pitch changing mechanism for automatically changing the speedsetting of said governor and having one position in which the governorsetting is below said range of normal speed settings, and acontinuously-open liquid-conducting conduit connecting said pitchchanging mechanism and said hydraulically-actuated governor speedsetting mechanism.

3. In combination with a propeller having hydraulically actuated pitchchanging means in which hydraulic fluid under pressure is introduced tosaid pitch changing means to change the pitch in one direction, agovernor controlling the introduction of said fluid, governor speedselecting means including hydraulically actuated means responsive to thehydraulic pressure in said pitch changing means for changing the speedsetting of the governor, and means continuously hydraulically connectingsaid propeller pitch changing means and said hydraulically actuatedspeed setting means to drain fluid from said hydraulically actuatedspeed setting means upon failure of the pressure in said pitch changingmeans.

4. In combination with a controllable pitch propeller having pitchchanging means in which hydraulic fluid under `pressure is introduced tosaid propeller pitch changing means to increase the propeller pitch, andfluid is drained from said propeller pitch changing means to decreasethe propeller pitch, said propeller being continuously urged toward lowpitch position incident to rotation thereof, a governor controlling theintroduction and draining of said fluid, governor speed selecting meansincluding hydraulically actuated means responsive to the pressure ofpitch changing hydraulic fluid being introduced to or drained from saidpropeller pitch changing means for. changingzy the-speed'. setting-r;offsaid. governor; and a conduiti continuouslyv hydraulicallyl con--Avnectlng the.. propeller side .of said ,goyernor, said. pitch`changing-"means and said/speed setting: means to`drainzsaid'hydraulically actuated meansr to reset the governor. toailower; speed value-upon".

failure of ther pitch'. changing. hydraulic` fluid pressureinzsaid:propeller pitch changing means;

5..In. combination; with'.`a controllable pitch propeller having ahydraulically-actuated pitchchanging mechanism and means-defining a lowpitchposition, saidtpropeller being continuously urged toward said lowpitch position incident to rotation thereof, a source of hydraulic uidunder pressure for operating said pitch changing mechanism, said pitchchanging mechanism being operable to increase the propeller pitch byapplication of said hydraulic fluid to said pitch changing mechanism andto decrease said propeller pitch by draining hydraulic fluid from saidpitch changing mechanism, a speed responsive governor having a range ofnormal speed settings, and a valve operated by said governor forcontrolling application of said hydraulic fluid to and the draining ofsaid hydraulic uid from said pitch changing mechanism, governor speedsetting means having a range of normal speed settings and a speedsetting below said range, hydraulically-actuated mechanism operativelyconnected with said speed setting means and responsive to the pressureof the hydraulic iluid in said pitch changing mechanism for changing thespeed setting of said governor between a setting below said range ofnormal speed settings and a normal speed setting, and continuously openfluid conducting means interconnecting said valve, saidhydraulically-actuated governor setting mechanism and saidhydraulically-actuated pitch-changing mechanism.

6. A propeller pitch controlling mechanism comprising, a fluid actuatedpitch changing motor, a speed responsive governor for controlling theapplication of iluid pressure to said motor to reduce the speed of thepropeller by increasing its pitch and for controlling the draining offluid from said motor to increase the speed of the propeller by reducingits pitch, a speeder spring for said governor, means for determining thespeed setting of the governor by locating the operating position of thespeeder spring, said means including iiuid operated means, responsive tothe fluid pressure in said motor, operably connected with said motor byuid conducting means for holding said Speeder spring in its operatingposition when the fluid in said motor is under pressure but movable toanother position by the Speeder spring to reset the governor for a lowerspeed upon failure of the pressure of the fluid in said fluid operatedmeans due to failure of the pressure of the fluid in said motor andcomprising a cylinder hydraulically connected. with said motor and apiston -reciprocable in said cylinder and operably associated with saidgovernor speeder spring.

'7. A propeller pitch controlling mechanism comprising, a fluid actuatedpitch changing motor, a speed responsive governor for controlling theapplication of fluid pressure to said motor to reduce the speed of thepropeller by increasing its pitch and for controlling the draining ofuid from said motor to increase the speed of the propeller by reducingits pitch, a Speeder spring for said governor, means for determining thespeed setting of the governor and locating the operating position ofsaid Speeder spring, said means including a. movable abutment` for saidspring, means for manually adjusting said abutment during operation ofthe propeller, a uid actuated expansible chamber device for moving saidabutment, and a continuously open fluid conducting conduit continuouslyoperatively connecting said expansible chamber device with said motorfor supplying operating fluid to said device.

NELSON R. RICHMOND.

REFERENCES CITED The following references are of record in the le ofthis patent:

Number Number 8 UNITED' STATES PATENTS Name Date Karelltz Nov. 22, 1938Caldwell et al Oct. 3, 1939 Lawrence -1 Jan. 7, 1941 Martin Oct. 28,1941 Dickey Nov. 4, 1941 Martin Mar. 7, 1944V Richmond July 4, 1944FOREIGN PATENTS Country Date France Nov. 6, 1937

